CIRCUITS AND DEVICES
COLLISION AVOIDANCE SYSTEM
As we all know, drivers can be distracted by cell phone calls, text messages, noisy construction work,
dripping cheeseburgers, nagging spouses, and a thousand
other things, making them dangerous to themselves and
others. Take your eyes off the road for even two seconds,
and the results can be disastrous. Mobileye
( www.mobileye.com), however, has introduced an over-the-counter solution: the Mobileye C2-270. The system is
a single-camera system for collision prevention, based on
the EyeQ2 vision chip. The chip is designed to detect
other vehicles, including motorcycles and bicycles, plus
pedestrians and even lane markings. The C2-270 consists
of three components: a windshield-mounted vision sensor
with a compact high dynamic range CMOS camera and
image processing board; an alert buzzer; and the
Eye Watch2 display and control unit. The smart camera
mounted on the inside of the windshield measures the
distance
(referred
to as
BETTER BATTERY MANAGEMENT
Also geared for safety, as well as efficiency in the automotive market, is Intersil's HEV/EV system, consisting of an automotive-grade Li-Ion
battery management system and safety monitor. The ISL78600 is designed
to address safety, reliability, and performance considerations for hybrid,
plug-in hybrid, and pure electric vehicles. In terms of safety, the system
provides ISO 26262 standard compliance to prevent battery pack failures,
plus fault detection for internal functions, as well as external faults such as
open wires, overvoltage, undervoltage, temperature, and cell balance
faults. Each device utilizes a 14-bit temperature-compensated data
converter that scans 12 channels in less than 250 microseconds.
Average mid-size HEV vehicles today use 126 to 168 cells, so
designers will need to include 11 to 14 chips per vehicle. When combined
with four external temperature sensors, the ISL78600 provides state-of-charge measurements across the full battery
operating temperature range. The unit can be connected to microcontrollers via either a 2. 5 MHz SPI or 400 kHz I2C
interface, and is specified for - 40 to 105°C operation. It will run you about $6.50 in manufacturing quantities. ▲
■ Intersil’s
ISL78600, an
automotive-grade Li-Ion
battery
management
system,
shown with
an ISL78601
battery
monitor.
■ Wolfson’s WM8958 audio hub.
MAJOR UPGRADE FOR SPEAKERPHONES
If you have ever tried engaging the speakerphone function on your cell, you will be fully aware of the tinny, almost
inaudible sound that results. However, Wolfson
Microelectronics ( www.wolfsonmicro.com) is aiming to fix
that courtesy of its WM8958 audio hub, a low power codec
designed to provide high definition, teleconference-quality
sound to phones as well as tablet computers, e-books, satellite navigation systems, and other portable appliances. The
three-channel audio hub provides 100 dB s/n during digital-to-analog playback while its integrated stereo class S/AB
speaker driver and Class W headphone driver reduce playback power consumption. An audio enhancement DSP runs
a three-band compressor to improve the sound from small speakers. Used with an on-board parametric equalizer and
dynamic range controller, the compressor can boost and optimize speaker outputs to improve audio playback quality.
A smart digital microphone interface provides power regulation, a low jitter clock, and decimation filters for up to four
digital microphones. Active ground loop noise rejection and DC offset correction help to eliminate pops and suppress
ground noise on the headphone output. According to Wolfson, the product is sampling now and will be ready for
production early this year. Products incorporating the WM8958 should begin appearing in the third quarter. ▲
12
February 2011
